Thank you Matthew. To be more accurate, my question is about the expected r-values indicating an existing connectivity between brainstem ROI to the cortical areas. I have not seen many articles reporting the values of the significant correlation coefficients and so I am wondering why it is not considered to be important.
In my case, I have found significant connectivity from the specific brainstem ROIs, but looking at the peak significant r-values, they are not exceeding 0.05. From the mathematical point of view, such a small r-value means the two compared variables are irrelevant; at the same time, it is not possible to ignore that the cortical pattern of these significant mathematical irrelevance seem to be meaningful. I believe that I am missing a point, where your expert opinion might help me to figure out. Thanks a lot, Amin On Mon, Jul 9, 2018 at 10:48 PM, Glasser, Matthew <[email protected]> wrote: > There is more unstructured noise in HCP data because of small voxel size > and fast TR. Basically that means the ratio between the neural signal and > the random noise is lower and that leads to lower correlation coefficients. > > > Peace, > > Matt. > > From: <[email protected]> on behalf of Amin Dadashi < > [email protected]> > Date: Monday, July 9, 2018 at 4:14 AM > To: hcp-users <[email protected]> > Subject: [HCP-Users] Brainstem to cortex baseline r-value > > Dear HCP users, > > Recently, I have tried to calculate the zero-order correlation between > some brainstem ROIs and the cortical vertices. Looking at the mean > subjects' correlation map, the connectivity pattern totally makes sense. > Even after doing the statistical testing (using permutation based on > maximum t-statistics) the significant correlated clusters are located in > the expected areas. However, the magnitude of the correlation coefficients > are very small (in the order of 0.05 for the peak vertices in the mean > map). I have also done the volume-based voxel-wise analysis for the same > brainstem ROIs and I had similar findings there. > Is there any explanation for such small r-values even though the > significant correlations seem to be meaningful? > > Thank you all, > Amin > > _______________________________________________ > HCP-Users mailing list > [email protected] > http://lists.humanconnectome.org/mailman/listinfo/hcp-users > > > ------------------------------ > > The materials in this message are private and may contain Protected > Healthcare Information or other information of a sensitive nature. If you > are not the intended recipient, be advised that any unauthorized use, > disclosure, copying or the taking of any action in reliance on the contents > of this information is strictly prohibited. If you have received this email > in error, please immediately notify the sender via telephone or return mail. > _______________________________________________ HCP-Users mailing list [email protected] http://lists.humanconnectome.org/mailman/listinfo/hcp-users
